Electric burner switch



Dec. 9, 1958 J. L. ANDREWS 2,863,971

ELECTRIC BURNER SWITCH Original Filed June 6, 1949 10 Sheets-Sheet 1 JQ/M ZEN/J 5/1/020 Dec. 9, 1958 J. L. ANDREWS 2,863,971

ELECTRIC BURNER SWITCH Original Filed June 6, 1949 10 Sheets-Sheet 2 -4 \\\\\\\\\;'E w Q 238 44 Q I90) 2 2 |c :l 1 are i T (I: 5 v I82 7 I83 Dec. 9, 1958 J. L. ANDREWS ELECTRIC BURNER SWITCH l0 Sheets-Sheet 3 Original Filed June 6, 1949 Dec. 9, 1958 J. L. ANDREWS 2,863,971

ELECTRIC BURNER SWITCH Original Filed June 6, 1949 sheets-sheet 4 OFF A IST HEAT A II ND HEAT IIIRD HEAT\ A a 20 m I63 V I M BETHHEAT 5 SETH HEAT Dec. 9', 1958 J. L. ANDREWS ELECTRIC BURNER SWITCH Origifial Filed June 6, 1949 10 Sheets-Sheet 5 Dec. 9, 1958 J. L. ANDREWS 2,863,971

ELECTRIC BURNER SWITCH Original Filed June 6, 1949 10 Sheets-Sheet 6 CONTROLS 42 8 CONTAC T CONTROLS 40a HORIZ- 436 CONTACT 9 5' ONTALLY 426 CONTROLS CONTACT 384 435 VERTICALLY CONTROL. THE LAMP 489 CONTACT CONTROLS 88 CONTACT384 407 CONTROLS HORIZONTALLY CONTACT 40s VERTICALLY Dec. 9, 1958 J. LTANDREWS- 2,863,971

ELECTRIC BURNER SWITCH Original Filed June 6, 1949 10 Sheets-Sheet 7 i Z 305' 5 3:5 f 1 iv WW Dec. 9, 1958 J. L. ANDREWS ELECTRIC BURNER SWITCH 10 Sheets-Sheet 8 Original Filed June 6, 1949 CONTACT 666 V/////// rL CONTACT 704 K CONTROLS CONTACT 7|7 9, 1958 J. L'. ANDREWS ELECTRIC BURNER SWITCH 1O Sheets-Sheet 9 Original Filed June 6, 1949 SIB 824 3 N. v 3 O 8 JIDI J .l m w 5/ q a F A A a n 8 6 85 a wfi 7/// I 7 a... 3 "w 6 y 7 7 MW 4 4 u W w 6 63 r J v I M L, L w v a 6 Original Filed June 6, 1949 TO CONTACT 644 Dec. 9, 1958 J. L. ANDREWS ELECTRIC BURNER SWITCH 10 Sheets-Sheet l O TO CONTACT TO CONTACTV 68l see United States Patent I 2,863,971 ELECTRIC BURNER SWITCH John Lewis Andrews, Chicago, Ill.

Original application June 6, 1949, Serial No. 97,425, new Patent No. 2,710,323, dated June 7, 1955. Divided and this application March 10, 1955, Serial No. 493,467

16 Claims. (Cl. 200-167} Thisinvention relates to multiple switches and more particularly to a switch'for use in conjunction with the burner of a domestic range.

The present application is a division of my application S. N. 97,425, filed June 6, 1949, for Electric Burner neutral conductors of a power source so that a variety of heats may be conveniently provided.

It is another object of the invention to provide a multiswitch of simple construction and utilizing a minimum number of parts.

It is a further object of the invention to provide a switch structure which may be economically manufactured.

It is an additional object of the invention to provide a switch structure having a minimum number of moving components.

It is a still further object of the invention to provide a multi-switch of the rotary type but so constructed as to have a lamp incorporaed therein for illumination of the face of the switch or for selective indication corresponding to various heats, wherein the lamp forms a part of the burner switching system and requires no extra mechanism for control.

Another object of the invention is to provide a switch mechanism such that a minimum number of previous metal contacts are required.

A further object of the invention is to provide a switch mechanism for use in conjunction with a particular system comprising heater coils and line conductors in such a manner as to effect a simple electrical combination therebetween; whereby a novel circuit is achieved.

Additional objects of the invention are to provide a switch which is unusually rugged in construction, easily assembled or dissembled, and having no fragile or delicate parts likely to get out of order.

In addition to all of the above objects a very important object of my invention is to provide a novel switching mechanism such that any danger of spark carry-over from one contact to another is virtually eliminated.

It is a well known fact that one of the drawbacks of rotary type switches of the prior art resides in spark carryover by the switch arm as it moves from one contact to the next succeeding contact. This is termed blow-out in the trade and may result in serious consequences under aggravated conditions wherein heavy currents are carried. The blow-out effect, which may result in a short circuit through the spark path, is frequently caused when the switch arm is moved too fast, so that it literally pulls the spark with itself-from a first contact to a second contact. Accordingly, it has been customary to move the switch arms of rotary switches slowly so as to give the spark a chance to damp out before the switch arm reaches the next succeeding contact By a novel, though simple construction, 1 effect a lengthening of the path of movement of the switch arm between contacts by providing a broken path for the arm; that is, the end of the arm in leaving a contact moves in a predetermined direction but prior to reaching the next contact changes direction, whereby the total length of motion of the contact end of the arm is 2,863,971 Patented Dec. 9, 1958 substantially increased and the time of motion in breaking engagement is relatively slow, though speeded up in passing from one contact to the next contact, the total time for the complete composite motion being depending on the design of the particular mechanism A further drawback of prior art switches is their complexity, especially where a large piurality of heatsis provided for; l overcome this by a novel arrangement of switching elements in conjunction with a pair of burner resistances which have two ends permanently connected in series, all as will hereinafter be described.

In general, my switch construction comprises a housing and a cam rotatably supported therin; a plurality of switch arms are also supported in the housing which arms cross over the cam segmentally and have an end fixedly joined to the housing at respective points while being free at their opposite ends. In order to effect as compact a construction as possible, I mount my switch arms on both sides of the cam, the cam being provided with arm actuating means comprising formations for engaging respective switch arms to deflect them in predetermined paths as the cam is rotated. The free ends of the arms carry contact for simultaneous selective engagement with, or disengagement from, certain other contacts which connect to the line and neutral conductors of the power supply. By utilizing a novel mode of connecting the burner coils and switch arms in relation to the line and neutral conductors, a minimum number of precious metal contacts are required. Further, a balanced load is achieved for certain heats.

in at least two forms of my invention, I show constructions wherein the arms and the arm actuating means on the cam are so formed and co-act in a manner such that as the cam is rotated to actuate one or more arms, depending on the specific circuit desired, the actuated arms disengage from stationary line conductor contacts in which they happen to be in engagement by moving initially in a substantially normal direction from such contacts. in other words, with reference to the axis of the rotary cam the free ends of the motivated arms first move in a direction parallel to the axis of the cam to disengage from the line conductor controls, whence continued rotation of the cam deflects the arms laterally to bring them opposite contacts with which they are to engage, and the final action of the cam drops the free end of the arms on the latter contacts. In order to achieve this co-action, I provide switch arms wherein each has two cam followers while the cam has individual formations co-acting with each of the followers. The arm actuating means on the cam for each switch arm is so devised as to provide the bi-planar motion, in angularly related paths, for respective switch arms in a sequential order as described above.

Another form of the invention provides for single plane motion of the arms and also of the line conductor contacts in such a manner so as to achieve a bi-planar effect as will be later described, wherein the switch arms are movable in one plane and the line conductor contacts are movable in different planes, and the cam is devised to motivate these members in a sequential order so as to preserve the angularly related motion therebetween.

In addition to the features hereinabove set forth, my novel switch structure also incorporates certain other unique features such as an indexing means, a color filter in conjunction with the lamp, etc. and many other constructional features of an improved nature.

With the foregoing objects, features and general description in mind, a detailed description of my invention and its various modifications will now be given in conjunction with the appended drawings in which:

Figure 1 is a plan view of the casing-showing one of for rotating the cam.

Figure 4 is a cross-section through 44 of Figure 3. Figure 5 is a cross-section through 5-5 of Figure 4.

Figure 5a shows schematically the reversible paths of :motion of the various switch arms.

Figure 6 is a perspective of the neutral bus. Figure 7 is a perspective of the switch arm shown in Figure 1.

Figures 8 and 9 show perspectives of other switch arms as used in this modification.

Figure 10 is a cross-section through 10-10 of Figure 3.

Figures 11a through 11h show diagrammatically the various circuits set up by the switch to provide seven selective heats.

Figure 12 is a top plan view of a second form of my invention.

Figure 12a is a perspective of a switch arm used exclusively for lamp control.

Figure 13 is a section through 1313 of Figure 12. I Figure 14 is a section through 14-14 of Figure 12. 1 Figure 15 is a view of the outer side of the cam. Figure 16 is a view of the inner side of the cam. Figure 17 is a sectional view showing certain details of the illuminating system.

Figure 18 is a plan view of the rotating knob.

Figure 19 is section through 1919 of Figure 12. Figure 20 is a perspective of one of the switch arms. Figure 21 is a perspective of another of the switch arms. Figure 22 is a perspective of the neutral conductor. Figure 23a through 23h is a series of circuit diagrams of the seven heats provided by this form of the invention.

Figure 24 is a plan view looking into the housing of a third form of my invention, comprising a five heat switch.

Figure 25 is a section through 2525 of Figure 24.

Figure 26 is a section through 26-26 of Figure 24.

Figure 27 is a section through 2727 of Figure 24.

Figure 28 is a section through 2828 of Figure 24.

Figure 29 is a section through 2929 of Figure 24.

Figures 30 through 34 are perspectives of'switch elements of this modification.

Figure 35 is a rear view of the housing showing the manner in which the various switch elements are secured thereto.

Figure 36 is a front view of the cam.

Figure 37 is a section of the cam through 3737 of Figure 25.

Figure 38 is a view in section showing the illuminating system of this form of the invention.

Figure 39 is a plan view of certain elements seen in Figure 38 and Figure 40a through f show circuit diagrams for the various positions of this five heat switch.

The switch arm and cam construction for efiecting bi-planar motion With reference now to the figures of the drawing, more particularly to Figures 1,. 3 and 7, and disregarding for the present certain structural details in order to focus attention on the essentials of the switch arm and cam coan arm actuatingformation or ridge 30 integral with a plastiodisc-like molded cam 40 upon rotation of the cam about its axis O-O, Figure 3. As shown in Figure 3a,

1 he in srotated by .a translucent plastic. knob 41 which keys into a collar 42 on the cam and houses an electric lamp disposed in the collar. The cam may be set in any of eight positions corresponding to an off and seven heat positions, being maintained in a selected position by an indexing means to be later described.

As shown on Figure 7, the arm 20 consists of an elongated member of any suitable spring-like metallic material formed with angularly related bends 43 and 46.

The arm 20 is affixed to the housing 10 by a rivet 51 (Figure 1) passing through a hole 54 (Figure 7) whereby the free end generally indicated at 57 may be deflected either laterally or vertically as seen in Figure 7, lateral deflection being by virtue of bend 43 while vertical deflection is provided by bend 46. Considering Figure 1, these deflections amount to a clockwise or counter-clockwise pivoting of the free end 57 about bend 43 and pivotal motion out of the plane of the paper of the free end about bend 46. As seen on Figure 3, arm 20 may deflect to the left away from L1 and also out of the plane of the paper, i. e., toward L2, as will be understood by comparing with Figure 4.

The body portion of arm 20 is slotted to provide a resilient tongue 60 which terminates in a pairof spaced guides 63 and 66, as shown on Figure 7 and as further represented on Figures 1 and 5. A shorter tongue is also provided in the slotted portion of the body, which latter tongue terminates in a V-shaped formation 73. The formation 73 as well as the guides 63 and 66 act as cam followers and protrude downwardly out of the plane of body member 20 so as to engage the arm actuating ridge 30 on cam 40. Thus it will be evident by comparing Figures 1 and 5 that the follower 73 rides atop the ridge. The top surface of the ridge is provided with a plurality of V-shaped depressions or notches 76 through 82 and it will be appreciated that as cam .40 is rotated the follower 73 may successively engage the various depressions 76 through 82 whereby to effect a rise-and-fall motion of arm 20 about bend 46. It will likewise be understood that follower 63, 66 is responsive to radial eccentricity of ridge 30; thus as cam 40 is rotated arm '20 will deflect about bend 43 to a degree depending on the point of engagement of the follower with ridge 30. In this connection it should be noted that the deflections of arm 20 are within the elastic limit of the material used. The importance of tongue 60 and its uniqueness is herewith stressed; owing to friction between follower 63,66 and ridge 30, there could occur a binding action which would prevent arm 20 from dropping of its own resilience to make contact, i. e., follower73 would not move into any of the notches. Tongue 60 renders arm 20 independent of this binding action owing to the fact that tongue 20 can flex downwardly to make contact even through tongue 66 may remain stationary should bindingoccur, i. e., the two tongues may flex independently of each other,

From the above description it willbe clear'that rotation of cam 40 effects a' motion of the free end' 57 of arm 20 such that initially it moves in' one direction and thereafter moves at'right angles tothe first direction. For example, assuming that follower 73 is engaged, say, in notch 81, it will be apparent from Figure 1 that upon counter clock-wise rotation of cam 40 arm 20 will first rise as follower 73 comes out of the'notch and no further motion of the arm will be experienced until the bend 84 of ridge 30 engages follower 63, 66; at this time the arm will be deflected toward the right since the radius from the center of the cam to the ridge 3t) begins to decrease after passing the cam portion 84. Continued rotation of the cam results ultimately in follower 73 being received in notch 89 at which time the free end 57 of the arm drops downwardly into the plane of the paper by virtue .of the resilience of the arm material. Thus, the motion of the free end 57 is initially upwardly, then to the right, and then downwardly. This bi-planar motion of the free end 57 of the arm provides a broken -lower surface of either contact L1 path of traverse for a precious metal contact 87 carried at the free end for purposes of engagement'with one or the other of a pair of fixed lino conductor contacts L1, L2 as indicated on Figures 1, 3 and 4. Contacts L1 and L2 are engageable from above, or on their upper surfaces, by contact 87 and are engageable on their lower surfaces by other switch arm contacts as will be hereinafter described. Further, contacts L1 and L2 arersupported by conductor buses 88 and 89 fixedly secured to the housing as by rivets 88 and 89', respectively, and the buses are connected to a 230 volt line as indicated in Figures-Z and 4.

Liberal arcuateness of bend 43 is provided so that contact 87 will have a sufiicient component of translational movement with respect to bend 43 to align with L2 at the end of its traverse, since L1 and L2 for manufacturing convenience do not lie on a true circle with respect to the motion of the arm. The bi-planar reversible path of motion of contact 87 may be seen diagrammatically on Figure 11, it being noted that contact 87 may engage only L1 or L2.

Two additional switch arms, as shown in Figures 8 and 9, are provided in this form of the invention; their general construction and co-action with cam 40 being similar to that just described for the switch arm 20. Figure 8 shows a switch arm 99 which will be understood to be formed of any suitable spring stock and being provided with bends 93 and 96 corresponding to bends 43 and 46 of arm 20.

In the case of arm 90, however, the flanges 99 and 103 which correspond to flanges 63 and 66 of arm 20, are formed upwardly so as to engage a ridge 107 on the lower face of cam40, as shown in Figure 4. In a similar manner the V formation 110 faces upwardly to form a cam follower for engaging the transverse exposed surface of ridge 107. Arm 90 is in other respects similar to arm 20 being fixedly secured in the housing by a rivet 112 as shown. The follower guides 99 and 103 are formed at the end of a tongue 113 while follower 110 is formed at the end of an opposing tongue 116. Further, the free end 120 of arm 90 is provided with a precious metal contact 123 (Figure 8) which is engageable with the or a neutral power contact N, Figures 3 and 4, it being noted that contacts L1, N and L2 are fixed in the same plane and are engageable from above or below that plane.

Contact N is supported by a bus 125 carried on the bottom wall of the casing in a manner to be hereinafter described, and is connected to the neutral conductor of the power line.

Referring now to Figure 4, the downwardly exposed surface of ridge 107 will be understood to be provided with a series of notches indicated as 127 through 132 and being shown in dotted lines on Figure 4 since they are in the downwardly disposed face of ridge 107.

The co-action between arm 90 and ridge 107 is substantial-ly the same as heretofore described for arm 20 and ridge 30. Thus, upon rotation of cam .0, arm 90 will be actuated in one direction initially and substantially at right angles to the original direction subsequently. By reference to Figure 50 it will be seen that contact 123 is motivated in a reversible path between the conductor contacts L1 and N; such motion being initially away from a conductor contact in a direction substantially normal thereto and thence transversely to the nextcontact and finally normally again upon engagement therewith, all as heretofore described in connection with arm 20.

The remaining arm of the switch 141?, is as shown in Figure 9 and will be seen to be a structure somewhat similar to arm 90 as shown in Figure 8 except for the fact that the vertical bend 146 is disposed on the opposite side as compared with bend 9 3 or" arm 90. Thus, as shown in Figure 9, arm 140 is comprised of a vertical bend 146 and a horizontal bend 149 to provide bi-planar motion of the free end 152. Follower guides 154, 157 and 160 are identical in construction with that heretofore described in connection with 99, 103 and 110 of arm 90. Similarly, a precious metal contact 163 is provided at the free end of the arm. Thus when arm 140 is mounted in the housing as shown in Figure 4, being fixedly secured thereto by a rivet 167, the follower guides 154 and 157 straddle an actuating formation comprised of the integral ridge 170 while follower 160 rides the exposed surface of the ridge. Ridge 170 is disposed outwardly of and surrounds ridge 197. This relationship will be clearly understood by comparison of Figures 3, 4 and 5.

A plurality of five notches 173 through 177 is indicated as shown by dotted lines on Figure 4, is provided for en agement with follower 160 as the cam is rotated. It be understood that the motion of'the arm 140 in response to rotary movement of the cam will be of a bi-planar nature as heretofore described for the other two arms of this form of the invention and by reference to Figure 5a the reversible and broken path movement of the contact 163 intermediate contacts L2 and N will be clear.

From the foregoing it is apparent that arm 20 co-acts only with contacts L1 and L2; arm 90 co-acts only with L1 and N, and arm 140 co-acts only with L2 and N.

In summation of the basic principles of operation of my switch, as thus far described:

A housing 10 carries therein a rotary cam 40 having a plurality of actuating means or ridges on both faces thereof. These ridges are radially eccentric and are provided with notches at predetermined points on the exposed surfaces thereof. Each ridge engages a respective switch arm, the arms being made of resilient spring material and so formed as to be defiectable in two planes substantially at right angles to each other. Each arm has cam followers for engaging its respective cams so as to respond to the radial eccentricity of the cam as well as to the notches on the surfaces of respective ridges. The switch arms have free ends provided with contacts which are adjacent three fixed power line conductor contacts L1, L2 and N in the housing. The radial eccentricity of each ridge is capable of deflecting, in one plane, its respective switch arm for alignment with either of two predetermined fixed line contacts. The notches in each ridge determine the initial and final motions in another plane of the free ends of the respective arms, either in breaking away from a fixed contact or making engagement with a fixed contact. The relative eccentricities and the relative positions of the notches of the respective ridges predetermine the particular engagement of certain of the switch arms with the line or neutral contacts for a selected rotated position of the cam.

It will now be clear from all of the foregoing that I have provided a fundamental mode of operation for a switch arm such that in making or breaking contact an elongated and bi-planar path is provided, whereby any danger of spark carry-over or blow-out is eliminated.

The arm positioning stations for the seven heats provided by this form of my invention are indicated in R0- man numerals on the several cam ridges shown in Figures 1 and 4; as is the off position indicated by Off.

Station Ridge 40 "Edge 107 ldge 17 Heat Notches Notches Notehes Number 78 129 None III 81 132 None VI 82 None 177 VII None None None 011 By comparing Figure 3 with the diagram of Figurellf, it Will be seen that the engagement of contact in Figure 3 corresponds to heat V. It will be apparent that as the cam rotates successive stations comprising eccentricities and/or notches actuate respective arms whereby any "circuit condition shown in Figure 11 may be obtained.

While I believe that persons skilled in the art will understand the mode of laying out the cam ridges to suit any desired conditions, for purposes of complete disclosure herein it may be stated that the basic principles involve initially an analysis of the circuits to be effected, e. g., as shown in Figure 11 to ascertain the successive motions of the switch arms required to efiect a change from one circuit to the next circuit, in the order of the power ratios or degrees of heat corresponding thereto. For example, starting with a circuit for highest heat (L) and drawing an electrical diagram for each of a series of successive steps in circuit change to ascertain switch arm motions, down to lowest heat (VII) precisely as shown in Figure 11, will enable a switch designer to drawn three cam layouts, each having eight (8) stations (to include an off position) at equally spaced corresponding points about a 360 transverse. Thus the problem involves conventional multi-cam design once the principles underlying my invention are understood.

The cam support, lamp base and indexing means Referring now to Figures 3, 4, and 5, it will be seen that collar 42 of cam 40 is concentrically received in a central bore 182 of a housing cover 183. As shown in Figure 1 diagonal corners of the housing are provided with shelves to receive screw holes 186 and it will be understood that the cover 183 is retained on the housing by virtue of screws (not shown) passing through the cover and fastening into holes 186. Cam 40 is maintained in proper position in the housing by the concentric shoulder 190 on cover 183, as seen in Figure 3, and also by a metal lamp base 193 which rotatably engages the base 194 of collar 42 in such a manner as to permit rotation of the cam. The lamp base is securely fixed to the housing by virtue of a pair of prongs 196 and 198 which pass through correspondingly disposed slots in the bottom of the housing (Figure 3) and also through arcuate slots 2%, 261 (Figure 6) in the neutral bus 125. Prongs 196 and 198 are clinched over as shown in Figures 2 and 3 and thus securely hold the neutral bus on the bottom of the housing as well as making an integral unit of the housing, the lamp base, and cam 40 though rotation of cam 40 is per- .mitted. Comparison of Figures 2 and 3 will make the relationship clear. The cam is further braced against any sidewise motion by having a necked-down portion 204 socketed in a shallow counterbore 206 in the bottom wall ofthe casing.

The lamp base 193 accommodates between its prongs 1 96 and 198, a tongue 210 which forms an extension of the bottom portion of the switch arm 20, as clearly shown on Figure 7.. The tongue 210 runs in a shallow groove 211 in the bottom wall of the housing which passes between the prongs 196 and 198; thus tongue 210 is centrally disposed therebetween to form a terminal for engaging the center contact of a lamp screwed into base 193. It will also be noted at this time that base 193 is in electrical contact with the neutral bus 125. The lamp is energized by virtue of the voltage existing between switch arm and the neutral bus 125, being 115 volts when arm 20 is in such a position that contact 87 engages either of the contacts L1 or L2.

An indexing means is provided for the cam 40 comprisinga star-shaped formation 212, as shown in Figure 10, being molded directly on the-cam just above the necked down portion 204 (Figure 3). The star-shaped area has eight troughs corresponding to seven heats and an off position and is wide enough axially to accommodate the thickness of a pair of discs 213 and 216 which are integrally carried on respective pins 219 and 222, the lower ends of the pins being of reduced diameter and rotatably and slidably engaged in slots 225 and 227 provided in the neutral bus 125. The upper end of each pin is slidably engaged in a slot 230 provided in cylindrical spring housings 235 and 238, respectively, molded at the bottom of housing 10. Housings '235 and 238 are molded so as to open outwardly at the bottom of the casing, being closed however by neutral bus 125 which acts as an end retainer for a spring 241 within housing 235, Figure 3. The outer end of housing 238 is closed in the molding thereof in order to serve as a retainer for a spring 244. Springs 241 and 244 bear against pins 219 and 222, respectively. Accordingly, the discs 213 and 216 are biased against the star formation (Figure 10) and as the cam is rotated they are forced into the troughs between the points of the star so as to act as resilient detents in holding the cam in any selected position. Moreover, inasmuch as the discs are mounted on pins which are rotatable in their respective slots, they cause no drag on the cam during its rotation, but rotate therewith.

The electrical circuit Referring now to Figure 11, and more particularly to circuit diagram a, the mode of connection of the heater coils A and B with switch arms 20, and 140 is illustrated. Coils A and B are connected in series at the burner. It will be understood that contact L1 and L2 and N are connected through their respective buses to the outside Wires and the neutral of a 230 volt line so that the voltage existing between N and either L1 or L2 is 115 volts. For the position shown in Figure 11a, contacts 87, 123, and 163 are out of engagement with the contacts L1, L2 and N, and are poised as shown with I relation to each other by the configuration of the cam;

and thus no current flows to either coil A or B. It will also be noted that no voltage exists across the lamp.

Figure 11b shows the circuit set up when cam 40 is rotated so as to provide contact between 123 and L1, 163 and L2 and 87 and L2. It will then be understood that coils A and B are in parallel across 230 volts and the lamp is across 115 volts. This circuit corresponds to the first or highest heat for the particular burner controlled. In like manner, rotation of the cam provides various positions of the three contacts 87, 123 and 163 as indicated in Figures through h. The several diagrams provide for six more heats of varying degree whence the total number of heats effectively provided by this switch will be seen to be seven. Mathematically there are ten possible circuit combinations for the three fixed and three movable contacts utilized in conjunction with a pair of coils wired as shown. Of the ten possible circuits, seven are used.

It will be readily understood that six other heats may be elfected when the following connections are made by rotation of cam 40 as follows:

2nd heat: Coil B across 230 volts, coil A being shunted by L1 out of the circuit, Figure 110;

3rd heat: Coil A across 230 volts, coil B being open at L2, Figure 11d;

4th heat: Coils A and B in parallel across volts, Figure lle;

5th heat: Coil B across 115 volts, coil A shunted across L1, Figure 11 6th heat: Coil A across 115 volts, coil B open at L2,

Figure 11g;

7th heat: Coils A and B in series across 115 volts, Figure 11h.

and contacts are doubled for eflecting the number of heats provided in my arrangement.

It will still further be apparent that I provide for illumination without the necessity of an additional switch contact or other swich mechanism for controlling on and ofl conditions of the lamp. This feature eflects an im portant economy as will be appreciated by those skilled in the art.

Further consideration of my switching arrangement indicates that development and changes are possible; thus adding two extra contacts, that in a pair of contacts, and coupling them electrically and mechanically with the structure hereinabove described, would yield additional circuit combinations. In other words, the broad principles set forth are applicable for the design of switches for any desired number of heats and in certain instances balanced circuits will result for various heats, depending on the particular circuit configuration and combinations used. For example, the first heat with the present arrangement effects a balanced load on the line. Were a heat desired wherein coils A and B are in series across 230 volts (not provided in the present embodiment) a balanced load would also result.

The broad electrical principle of my invention will now be appreciated, namely, a combination of burner coils permanently connected in series and connected to various movable switch arms in such manner that a lamp may be energized by one of such switch arms, which, except for the off position, is engaged with one or the other of a pair of line contacts. Thus, by referring to Figure 11, it will be noted that arm 20 is always at a 230 volt potential, except for the off position. In other words, one end of the coil A is always at a 230 volt potential. When coil A, however, is not used in any particular circuit, it is shunted across contact L1, thereby placing the other end at 230 volt potential and like polarity at any instant. Accordingly, no current can go through coil A although the lamp remains energized.

The form of the invention shown in Figures 12 to 23 comprises four switch arms designated as 305, 310, 315 and 320. The switch arms are fastened to the housing 300 by being bolted or riveted to shelves 325, 330, 335 and 340, respectively, which are formed in the end wall of housing 300 as shown in Figure 19. In this manner the four switch arms are maintained at their proper respective levels for co-action with a molded plastic cam 345 to be hereinafter described. The connections to the burner coils A and B are shown in Figure 12.

The switch arms and cam co-action With reference now to Figure 20, a perspective of switch arm 305 is disclosed wherein it is seen to be comprised of two arm elements 350 and 353 formed from a sheet of spring stock. These elements straddle cam 345 as shown in Figure 12. Element 350 (Figure 20) is joined by a bend 356, while element 353 is joined by a bend 360, to a section 364 which in turn is joined by a bend 368 to a flange 371. Flange 371 is connected by a bend 374 to a flange 377. Flange 377 is integral with a flange 380 for fastening to shelf 325.

The free end of arm element 350, which carries a precious metal contact 384, is thus deflectable by virtue of bend 356 in an upward or downward direction as viewed on Figure 20. Further, by virtue of bends 364 and 374, the free end of the element 350 is deflectable in a horizontal plane. Thus by referring to Figure 12, it will be understood that arm element 350 may move to the left and also into the plane of the paper as may be seen by noting Figure 14 which shows element 350 to be in its outermost position. Referring back to Figure 20, it will be seen that the arm 350 comprises a flange 387 in which a V-shaped crimp 390 has been formed thus permitting the formation of another V-shaped crimp 394 in the arm portion proper, which crimp extends downwardly out of the plane of the arm and serves as a cam 10 follower in co-action with cam 345 having certain notches, later described, on a ridge 395 to provide rise-and-fall motion of element 350 as zllower 394 rides out of or into the notches, respectively.

The lower arm element 353 of switch arm 305 terminates in a pair of arcuately shaped flanges 396 and 398 which together form another cam follower for co-action with an eccentric groove 460 in cam 345 at its underside, as seen on Figures 12 and 13.

Cam groove 400 is laid out so that contact 384 can engage only contacts L2 or N which are connected to power.

The details of arm 320 (Figure 12) are not separately shown but will be understood to be similar to those for the arm 305 except for being reversed in position. For example, arm element 401 (Figure 12) corresponds to arm element 353 except that it is positioned on top of the cam while arm element 404 corresponds to element 350 except that it is positioned to engage on the undersurface of the cam; elements 401 and 404 straddle cam 345, element 401 having follower flanges 402, 403 for engaging a groove 405 in the top surface of the cam, while element 404 has a V-shaped follower 406 protruding downwardly to engage certain notches, later described, in a ridge 407 on the bottom surface (Figure 16).

The arm element 404 carries at its free end a contact 408 and groove 405 is laid out so that contact 408 engages contacts L1 or N only, being connected to the power.

Thus contact 384 and 408 are engagable from above and below, respectively, with the power contacts as will be clear from Figure 14.

Contacts L1 and L2 are connected across 230 volts while N is connected to neutral for volts. These three contacts are held in fixed position in the same plane by buses to be hereinafter described.

By referring to Figures 12 and 14, it will be seen that contact 408 is in engagement with the neutral contact, contact 384 being raised thereabove (Figure 14). This condition corresponds, by way of illustration, to the seventh heat as may be seen by referring to the circuit diagram for the seventh heat in Figure 23h.

Referring now to Figure 21, the arm 315 is shown in perspective and is seen to comprise a body member 410, a bracing side flange 413 and V-shaped crimps 416 and 419 in the body and the flange members, respectively. The crimped formations are substantially the same as heretofore described in connection with Figure 20, crimp 419 being necessitated in order to obtain crimp 416, in a manner which will be understood by a person skilled in the art. Arm 315 terminates in a flange 423 for fastening to the housing and the free ends of the arm carries a contact 426. This arm is positioned above the cam 345 so that the crimp 416 acts as a cam follower engageable with certain notches provided in a ridge 423 on the upper surface of the cam as indicated in Figures 12, 13 and 14. It will be noted at this point, however, that arm 315 is capable of deflection only in an upward or downward direction as viewed on Figure 21, or out of the plane of the paper as viewed on Figure 12, being stopped from motion into the plane of the paper by engagement with fixed contact L1. In other words, contact 426 is capable of engaging with or disengaging from the upper surface of contact L1 but is not capable of deflecting into alignment with any other contact such as N or L2.

Switch arm 310 is generally similar to the construction just described for arm 315 except that it is formed reversely for mounting below the cam. Thus a V-shaped follower 430 (Figures 12 and 12a) is formed so as to protrude upwardly out of the plane of the arm for engagement with certain notches on a ridge 431 (Figure 14) on the under surface of the cam. The free end of arm 310 carries an embossed contact 434 and it will be noted that this arm is capable of deflection only into the 11 plane of the paper as viewed on Figure 12 so that it can engage with or disengage for the lower surface of contact L2 but cannot move out of alignment therefrom for engagement with contact N or L1. A tongue 435 is formed at the base of arm 310 and extends between the prongs 436 of the lamp base to form a center terminal thereof (Figure 14).

Thus contacts 426 and 434 are restricted to single plane motion for co-action with, and only with, contacts L1 and L2, respectively.

Power line contacts The contacts L1, L2 and N are comprised of precious metal and are all fixed in a common plane, as heretofore mentioned, L1 and L2 being carried at the ends of buses 437 and 440, respectively, which are suitably fastened to the housing as indicated in Figure 12 which also shows the specific power connections. The neutral contact N is carried by a bus 445 (shown in perspective in Figure 22) comprising a body portion 447, an upright section 450 and a horizontally extending flange 453 which is bent reentrantly on itself and extends rearwardly sufficiently to maintain contact N on an extremity 456 in proper position with respect to the line contacts and cam elements 350 and 404. I

The cam construction The Figures 15 and 16 show the outside and inside faces of the cam 345 respectively, to a somewhat reduced scale, illustrating the relationship of the eccentric grooves and the notched ridges. All formations are designated by legends to indicate, with reference to the plan view of Figure 2, the particular functions of the grooves and ridges. For example, the under side of the cam (Figure 16) has ridge 407 formed thereon. The ridge has a plurality of notches 488 through 492 formed therein which accommodate follower 406 to provide engagement of contact 408 with either N or L1 depending on the degree of rotation of the groove 405 (Figure 15) which controls the horizontal position of contact 408 by virtue of engagement with follower 402, 403.

In a similar manner contact 384 may be brought into engagement with contact N or L2 when the V-shaped cam follower 394 on arm element 350 drops into one of the series of notches 505 through 510 on the ridge 395; depending on the rotated position of groove 400 Which engages follower 396, 398 to determine aligning of contact 384 with either N or L2. On the upper surface of the cam, as shown in Figure 15, is the ridge 428 having a plurality of spaced notches 518522 for engaging the follower 416 of switch arm 315. Thus contact 426 on arm 315 isdeflected into or out of the plane of paper as viewed on Figure 12 to engage or disengage contact L1, as heretofore described.

By referring to the wiring diagram of Figure 23, it will be seen that the arm 310 is used solely for switching the lamp on and off at each heat period, thus seven notches 530 are provided in ridge 431 (Figure 16) corresponding to the seven heats of this particular switch and each time the other switch arms are engaged with certain contacts for setting up a particular circuit comprising the coils A and B, contact 434 of the arm 310 will engage the lower portion of contact L2 to thus energize the lamp across L2 and neutral contact N.

As seen on Figures 15 and 16, Roman numerals are used to designate locations on the ridges corresponding to respective heats, there being notches required at some points but not at others as will be understood by referring to Figure 23; e. g., on ridge 395 there is no notch for the off position or heat VII. On ridge 428 there is no notch for the ofi position or heats III and VI; while on ridge 407 there are no notches for the off position or heats II and V.

In order to clarify Figure 12 as to which contacts are above and which are below the fixed contacts L1, L2 and N. Figure 23a represents diagrammatically the actual physical configuration insofar as relative vertical spacing of the various contacts is concerned.

General assembly and indexing of the cam By referring to Figure 14, the mode of fastening the neutral bus 445 by'means of prongs 436 to the body 300 will be apparent, as will also be the indexing of the cam, which indexing mechanism is substantially the same as has been heretofore described, spring biased discs 535, 538 being utilized to resiliently engage a star formation molded on the cam substantially as shown in Figure 10.

Thus the cam, lamp base, neutral bus assembly and indexing means is substantially the same as heretofore described in connection with the form shown in Figures l-ll; the cam being relatively supported for engagement with and actuation of the switch arms and being settable in any of eight angular positions corresponding to an off position and seven selective heats.

The control knob and illuminating system By referring to Figures 13, 14, 17 and 18, the knob control and illumination system of my switch will be apparent. A metallic nipple 550 (Figure 13), having a slot 553 (Figure 17) at its lower end, keys on to a projection 557 formed internally in the collar 560 of the cam 345. A translucent plastic knob 563 is forced fitted The electrical circuits Figures 23a through h illustrates diagrammatically the off-position and the positions of the various contacts for effecting the seven heats. Note that contacts 426 and y 434 make or break with L1 or L2, respectively, and do not engage any other contacts in the system. Contact 434, which energizes the lamp, is in engagement with L2 for all heatsas heretofore mentioned and as provided for by the seven notches 530 (Figure 16). Note further that contact 408 makes or breaks with contacts N or L1, only, while contact 384 makes or breaks with contacts N or L2, only, all as heretofore specified.

An advantage of this particular switch construction resides in the use of the extra arm 310, which if desired, could be utilized to provide extra heats for the switch. While switch arm 310 has been dissembled as provided with an embossed contact 434, it will be understood that in the event extra heats are intended, a precious metal contact may be provided. However, for purposes of switching the relatively low wattage lamp on and off an embossed contact is sufiicient.

It will be apparent that the modification described provides for bi-planar motion for two contacts only, i. e., 384 and 408, but it should be noted that these are the two controls which are required to move between the power contacts L1 and N or L2 and N, whence the advantage from a standpoint of preventing arcing over between the latter controls is preserved. Contact 426 on the other hand is engageable only with contact L1 and accordingly single direction motion is adequate although not as desirable as bi-planar motion would be for the purpose of attenuating any are which might be caused upon disengagement.

The form of the invention disclosed in Figures 24-40 comprises a' molded casing 600 wherein is rotativel'y mounted a cam 605, in a manner heretofore described, by

means of clinched prongs 608 and 611 (Figure 27) of a lamp base 614. The prongs pass through holes 617 and 621 of a switch arm 625 (Figure 34) and thus secure the base section 627 of the arm to the bottom wall 630 (Figure 35) of the casing. The arm 625 is comprised of suitable spring stock and is formed as shown in Figures 27 and 34 so as to pass upwardly through a slot 633 in the bottom wall and around a shelf 636, being provided with perforated flanges 639, 640 through which it is riveted to the shelf. The free end of the arm carries a precious metal contact element 644 while intermediate of the arm a cam follower 647 is provided in a manner heretofore described in the other modifications. By virtue of the bend 650 (Figure 34) it will be appreciated that the contact 644 may be deflected into or out of the plane of the paper as viewed on Figure 24, or to the left or right as viewed on Figure 27, the arm being thus limited to motion in a single plane.

In a similar manner a switch arm 655 is fashioned (Figure 33) having a pair of perforated flanges 658, 659 by virtue of which it is secured by rivettng to the bottom Wall of the casing (Figure 35); a Z-shaped slot 662 being provided therein to facilitate the assembly as will be understood by comparing Figures 28 and 35.

Arm 655 is provided with a cam follower 663 and a precious metal contact 666 at the free end thereof and by virtue of bend 669 will be understood to be deflectable into or out of the plane of the paper as viewed on Figure 24, or to the left or right as viewed on Figure 27; thus being also limited to motion in a single plane.

A third arm 672 (not shown separately) extends across cam 605 (Figure 24) in a manner similar to arms 625 and 655, which arm is likewise secured by flanges, the outer of which, 675, is visible in Figure 35. Arm 672 is also provided with a cam follower 678 and a precious metal contact 681 and by virtue of bend 684 is deflectable in a single plane similarly to the other two arms.

Below the cam are disposed a pair of arms 688 and 692 as shown in perspective in Figures 31 and 32, respectively. These arms are likewise formed of spring stock and comprise perforated flanges for attachment to the bottom Wall of the casing as indicated in Figure 35 by reference characters 695 and 698 signifying the lower flange in each instance. Arm 692 may be seen in side view on Figure 28 whereas arm 698 is visible on Figure 27. It is understood that the housing is suitably slotted as at 701 (Figures 27 and 35) for assembly of these arms therewith. Arm 692 is provided with a precious metal contact 704 and the side walls of the arm are formed to effect a cam follower 707 (Figure 32) by means of projections of arcuate shape as shown. A bend 710 is provided to properly position the arm and it is deflectable to the left, as viewed on Figure 24, by virtue of a wall 714 of suitable length to provide suflicient flexure. In a similar construction, arm 688 has a contact 717, a cam follower 720, a bend 723, and a suitably deflectable wall 726.

The final arm 730 in this modification is as shown in Figure 30 and comprises a member suitably shaped to fit below the cam as shown in Figures 24 and 37, being of generally planar aspect from a bend 733 to a contact 736 and assembled in the casing by virtue of slot 662 (Figure 35), being riveted therein by virtue of perforated flanges 740 and 742. A tongue 745 on arm 730 is provided extended between lamp prongs 608 and 611 to form the central terminal of the lamp base.

It will be noted that arm 730 has no cam follower; it is not controlled directly by the cam but by arm 655 which has only a rise-and-fall motion and is at all times aligned at its contact 666 with contact 736 as shown in Figures 24 and 27. Except for the off position as shown in Figure 40a, contacts 666 and 736 are always engaged; and by suitable choice of spring stock arm 655 dominates arm 730. It will be seen from Figure 27 that cam 605 acts as a stop for cam 730 in the upward direc tion and by virtue of the dominating characteristic of arm 655 contact 736 may, under certain conditions, be forced downwardly to engage contact 717 of arm 688. This condition, is of course, brought about by the action of the cam on arm 655, as will be later explained, and is required for the first and third heats as will be noted on Figure 40.

This, with reference to the plan view of Figure 24, the arms above the cam, i. e., 625, 655, 684 move in a horizontal plane, while the arms below the cam move in a vertical plane.

Referring now to Figures 36 and 37 showing the upper and lower surface of cam 605, respectively. Figure 36 discloses a plurality of notches for controlling contacts 644, 666 and 681 while Figure 37 shows the underside of the cam as a section through 37-37 of Figure 25 revealing two grooves for controlling contacts 704 and 717. The engagement relationship of these several contacts with respect to each other is shown in Figure 40 as heretofore mentioned, and should be referred to in the discussion which follows.

The relative positions of the several cam followers is indicated on Figures 36 and 37 and it will be noted that the configuration is as found in Figure 24, which corresponds to heat I as shown in Figure 4012. Thus followers 787 and 720 engage in a pair of respective grooves 746 and 748 for providing transverse motion of contacts 764 and 717 respectively. Groove 748 actuates follower 720 for alignment of contact 717 with either contact 644 or 736. Engagement with 736, is, however, controlled by arm 655 as heretofore explained. Groove 746 actuates follower 707 to align contact 704 with contact 736 or contact 681.

Follower 663 is shown engaged in a notch 749 (heat I) and is engageable as the cam rotates in notches 7.58 through 753 successively. Likewise follower 678 is shown engaged in a notch 754 and is engageable in a notch 755. Follower 647 is not engaged in a notch for heat I but as the cam rotates it is engageable in notches 756, 757 and 758, successively. By referring to Figure 40b and d it will be seen that there is engagement between contacts 686, 736 and 717. Thus a condition is brought about whereby dominant arm 655 (Figure 27) forces arm 730 downwardly to effect this triple engagement. This is achieved by making notches 749 and 751 relatively deep to cause cam follower 663 to drop sufficiently to permit arm 655 to force arm 730 downward away from the supporting undersurface of the cam. For heats I and III the triple engagement is thus effected by suitable depth of notches 749 and 751. On the other hand for heats II and IV, it is not desired to have engagement between contacts 717 and 736 and accordingly, notches 758 and 752 which control contact 666 for these heats are made shallow so as to prevent arm 655 from forcing arm 730 downwardly.

The depth of all other notches may be deep or shallow, but preferably deep, although this is not critical since relative depths for desired circuit conditions is required only of notches 749, 758, 751 and 752.

It should be particularly noted that notches which are radially aligned on Figure 36 are not necessarily for the same heat, Thus for heat I notches 749, 754 only are utilized; for heat 11 notches 750, 755 are utilized; for heat III notches 751, 756 are utilized; for heat IV notches 752, 757 are utilized; for heat V notches 753, 758 are utilized. For the ofi position all cam followers ride the surface of the cam, except, of course for those below the cam.

From all the above it will be seen that contact 736 is always engaged with contact 666 except for the oil? position, and by referring to Figure 40 the lamp is seen to be energized for all five heats. The mode of connection for the heater coils A and B is shown in Figure 35 and also the power connections.

From the above description it will be evident that this modification provides relative bi-planar motion of the switch arms, even though each arm is movable only in a single plane. However, the upper arms are always actuated by their respective notches prior to actuation of the lower arms by their respective grooves, by proper layout of the cam, so that engagement or disengagement initially occurs in a direction normal to the plane of the paper as viewed on Figure 24, followed by transverse motion of the lower arms with continued rotation of the cam.

Indexing of the cam is accomplished by molding a six pointed star thereon, thus forming recesses 803 for receiving discs 806 and 810. See Figures 24, 29 and 36. The disc arrangement is substantially as heretofore de scribed in connection with the other modifications except that the supporting grooves 813 and 815 (Figure 29) for the ends of pin 818 are formed in the housing and cover 821, respectively. Bolt holes 822 (Figures 24 and 26) are provided for securing the cover to the housing. A spring 824 is utilized for biasing disc 806. All the structure just described will be understood to be duplicated for disc 810, although it is not shown. Thus indexing for an off and five heat positions is accomplished.

A mode of illumination for the front of the switch is shown in Figures 38 and 39, on a reduced scale. A collar 827 is formed integral with the cam, in which is located a lamp that will be understood to be secured in lamp base 614 as shown in Figure 27. Supported on the collar 827 is a molded toroid 830, of any suitable transparent material having a shoulder 833 formed therein to rest on the collar. Toroid 830 is formed with six flat integral reflector surfaces 836 directly below six bulbously formed lenses 839. The arrangement is hexagonal as shown in Figure 39 to correspond to an off and five heat positions in a circular layout. Secured concentrically within the central opening of the toroid is a colored filter sleeve 842. A knob 845 is secured to a metallic sleeve 848 which keys within collar 827 in a manner hereinbefore described for rotating the cam. An aperture 851 is cut into the sleeve 848 through which light rays from the lamp pass to the reflector surfaces 836 successively as the knob 845 is rotated. Thus each lens 839 in turn receives reflected light as the knob rotates, the light being concentrated by the lens action in each case and made highly visible for any particular heat depending upon the knob setting. The structure may be mounted contiguous with a range front 851 suitably apertured as shown so that the lenses protrude therethrough.

Having thus described my invention, I am aware that many modifications may be made thereof; for example, the double surface contacts may be modified so as to be replaced by a pair of separated contacts; further, the switch arms for bi-planar motion may be pivotably mounted whereby deflection in one plane occurs by reason of bending of the arm material. Various cam and arm designs are possible for accomplishing my teaching and the basic principles of the other features of my invention are also subject to utilization in various embodiments;

Accordingly, I do not seek to be limited to the specific construction described hereinabove, except as set forth in the appended claims.

I claim:

1. A selective multi-switching arrangement and mechanism for obtaining a plurality of selective circuits in a system fed by two line conductors and a neutral con ductor, comprising in combination, a pair of current consuming devices connected in series, each end of one of said devices having a respective movable conductor permanently connected thereto, and means rendering said movable conductors connectable with one, only, of said line conductors or said neutral conductor, and a third movable conductor permanently connected to the outer end of the other of said devices, and means rendering said latter conductor connectable with either of said line conductors but not with said neutral conductor, including an illuminating lamp permanently connected across said third movable conductor and said neutral conductor, whereby said devices and said line and neutral conductors may be connected in a plurality of combinations, and means for disconnecting all of said movable conductors from said line and neutral conductors in deenergizing both of said devices, said lamp being thus energized only when said third movable conductor is connected to one of said line conductors, and being denergized when said conductor is not connected to either of said line conductors.

2. A switching system and mechanism for variably connecting two line conductors and a neutral conductor to a pair of coils so as to effect a plurality of individually selective circuits therebetween; comprising a housing, two

line conductor contacts therein; a neutral conductor contact therein, a rotary cam therein, a plurality of switch arms having respective ends joined to said casing and having free ends engageable selectively with a respective line conductor contact for said neutral contact, a pair of coils exteriorly of said housing and having a common connection, said common connection being connected to one of said switch arms and the other ends of said coils being each connected to a respective switch arm, said cam having individual arm actuating means engaging individual arms and efiective to deflect said arms to or from said certain contacts upon rotation of said cam to a selected position, for achieving a predetermined'circuit between said coils and contacts dependent upon said selected position of said cam. V

3. A switching system and mechanism as set forth in claim 2, wherein said cam comprises a disc-like member having an open collar extending axially therethrough, said housing having a bottom wall adjoining and closing the lower open end of said collar, a lamp base in said collar opening upwardly therein to receive a lamp and terminating downwardly in a pair of prongs passing through said bottom wall, a conductor electrically connected to said neutral contact and disposed on the exterior of said bottom Wall, including slots in said conductor through which said prongs extend to secure said conductor and to establish an electrical connection between said conductor and said lamp base.

4. In a rotary switch mechanism, a housing, an actuating element rotatively mounted in said housing and comprising a circular cam having an axial opening, a lamp base in said opening, a color filter co-axial with said lamp base, a tubular shaft keyed to said cam axially thereof and having an aperture therethrough disposed beyond said lamp base for alignment with a lamp filament, and a transparent knob secured to said shaft and having an internal reflecting surface disposed in relationship to said aperture for reflecting rays therefrom in a generally axial direction.

5. In a rotary switch mechanism, a housing, an actuating element rotatively mounted in said housing and comprisinga circular cam having an axial opening including a lamp base therein for a source of light, a tubular shaft keyed to said cam axially thereof and having an aperture therethrough, a knob secured to said shaft outwardly of said housing and a transparent toroid surrounding said shaft and having a plurality of reflecting surfaces successively alignable with said aperture for reflecting light therefrom in a generally axial direction, including a lamp base in said opening.

6. In a rotary switch mechanism, 'a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture ex- 9 .S id shaft in any rotated position of said knob,

and toroidal reflective means disposed exteriorly of said shaft and having a plurality of internal surfaces upon which said light rays impinge to change the direction thereof, each of said surfaces being alignable with said aperture as said shaft is rotated.

7. In a switch as set forth in claim 6, including a color filter intermediate said shaft and said reflective means.

8. In a switch as set forth in claim 6, wherein said lamp is concentric with said shaft and disposed substantially therein.

9. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exteriorly of said shaft in any rotated position of said knob, and reflective means having an internal reflective continuous surface concentrically surrounding said shaft upon which said light rays impinge to change the direction thereof, said internal reflective surface being angularly related to said shaft so that light rays from said aperture may impinge on some portion of said surface in any rotated position of said shaft; there being relative rotation between said shaft and said reflwtive means.

10. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exterioly of said shaft in any rotated position of said knob, and reflective means disposed exteriorly of said shaft upon which said light rays impinge to change the direction thereof, said knob being made of translucent material, said reflective means comprising an interior surface of said knob and in alignment with said aperture, said surface being slanted with respect to the rotary axis of said knob whereby light rays reflected from said surface are generally directed parallel to the rotary axis of said knob.

11. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exteriorly of said shaft in any rotated position of said knob, and reflective means disposed exteriorly of said shaft upon which said light rays impinge to change the direction thereof, including a color filter intermediate said shaft and said reflective means, wherein said lamp is concentric with said shaft and disposed substantially therein, said reflective means being carried by said knob and disposed in alignment with said aperture, said reflective means comprising an interior surface of said knob.

12. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exteriorly of said shaft in any rotated position of said knob, and reflective means disposed exteriorly of said shaft upon which said light rays impinge to change the direction thereof, including a color filter intermediate said shaft and said reflective means, wherein said lamp is concentric with said shaft and disposed substantially therein, said reflective means comprising a plurality of reflective surfaces arranged in respective predetermined positions about the arc of traverse of said aperture, each surface in turn effecting reflection as said shaft is rotated.

13. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exteriorly of said shaft in any rotated position of said knob, and reflective means disposed exteriorly of said shaft upon which said light rays impinge to change the direction thereof, including a color filter intermediate said shaft and said reflective means, wherein said lamp is concentric with said shaft and disposed substantially therein, said reflective means comprising a plurality of reflective surfaces arranged in respective predetermined positions about the arc of traverse of said aperture, wherein said surfaces are formed on a translucent ring surrounding said shaft and being stationary with respect thereto, each surface in turn effecting reflection as said shaft is rotated.

14. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exteriorly of said shaft in any rotated position of said knob, and reflective means disposed exteriorly of said shaft upon which said light rays impinge to change the direction thereof, said reflective means comprising a plurality of reflective surfaces arranged in respective predetermined positions about the arc of traverse of said aperture, wherein said surfaces are formed on a translucent ring surrounding said shaft and being stationary with respect thereto, said translucent ring being provided with integral lenses having respective reflective surfaces, the optical axes of said lenses being generally parallel to the axis of rotation of said knob and said reflective surfaces being slanted with respect to said axis of rotation so as to reflect light rays from the interior of said shaft through re spective lenses.

15. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exteriorly of said shaft in any rotated position of said knob, and reflective means disposed exteriorly of said shaft upon which said light rays impinge to change the direction thereof, including a color filter intermediate said shaft and said reflective means, wherein said lamp is concentric with said shaft and disposed substantially therein, said reflective means comprising a plurality of reflective surfaces arranged in respective predetermined positions about the arc of traverse of said aperture, wherein said surfaces are formed On a translucent ring surrounding said shaft and being stationary with respect thereto, said translucent ring being provided with integral lenses having respective reflective surfaces, the optical axis of said lenses being generally parallel to the axis of rotation of said knob and said reflective surfaces being slanted with respect to said axis of rotation so as to reflect light rays from the interior of said shaft through respective lenses.

16. In a rotary switch mechanism, a switch-actuating knob having a hollow shaft and an aperture in said shaft, a lamp disposed to illuminate the interior of said shaft whereby light rays may pass through said aperture exteriorly of said shaft in any rotated position of said knob, and reflective means disposed exteriorly of said shaft upon which said light rays impinge to change the direction thereof, wherein said lamp is concentric with said shaft and disposed substantially therein, said reflective means comprising a plurality of reflective surfaces arranged in respective predetermined positions about the arc of traverse of said aperture, wherein said surfaces are formed on a translucent ring surrounding said shaft and being stationary with respect thereto, said translucent ring being provided with integral lenses having respective reflective surfaces, the optical axis of said lenses being generally parallel to the axis of rotation of said knob and said reflective surfaces being slanted with respect to said axis of rotation so as to reflect light rays from the interior of said shaft through respective lenses.

References Cited in the file of this patent UNITED STATES PATENTS 1,997,258 Krieger Apr. 9, 1935 2,043,054 Marty et al. June 2, 1936 2,109,790 Batcheller Mar. 1, 1938 2,242,165 Batcheller May 13, 1941 2,437,555 Rees Mar. 9, 1948 2,462,594 Beal Feb. 22, 1949 2,748,206 Andrews May 29, 1956 

